Catalytic reforming of hydrocarbons



United States Patent ice CATALYTlC REFORMING OF HYDROCARBONS Kenneth Hugh Bourue and Peter Thomas White, Sunhury-on-Tharnes, England, assignors to The British Petroleum Company Limited, London, England, a jointstock corporation of Great Britain No Drawing. Filed Aug. 18, 1959, Ser. No. 834,404 Claims priority, application Great Britain Aug. 27, 1958 2 Claims. (Cl. 208-136) This invention relates to the dehydrogenation or dehydrocyclisation of non-aromatic hydrocarbons.

Catalysts of chromium oxide on a support, for example, alumina are known to have dehydrogenating and dehydrocyclising properties and various promoters have been proposed for improving such catalysts.

It has now been found that minor amounts of beryllium in combination with other promoters can improve supported chromium oxide catalysts and according to the present invention a process for the dehydrogenation or dehydrocyclisation of feedstocks consisting of or containing non-aromatic hydrocarbons comprises contacting the feedstock at a temperature of from 450 to 580 C. with a catalyst comprising chromium oxide on a support preferably alumina, the catalyst containing also a minor proportion (with respect to the chromium oxide) of beryllium and a minor proportion (with respect to chromium oxide) of an alkali metal, preferably potassium.

The beryllium and the alkali metal are preferably present in the form oxides. Preferably minor amounts, with respect to the chormium oxide, of one or more other promoting elements are present also, for example nickel, or cobalt. A catalyst containing minor amounts of beryllium, potassium and nickel is particularly preferred. The preferred proportions of catalyst components, by weight of total catalyst stable at 550 C., are:

Percent Chromium oxide (expressed as Cr O 5 to Beryllium (expressed as BeO) 0.1 to 5 Potassium (expressed as K 0) 0.1 to 5 Other promoting elements (expressed as oxide) 0.1 to 5 Alumina Balance The process is preferably carried out at a pressure of not more than 50 p.s.i.g. without the addition of extraneous hydrogen and without recycle of the hydrogencontaining gas produced in the process. An appreciable quantity of such gas is produced, which is available as a valuable by-product. The term not more than 5 O p.s.i.g. includes atmospheric pressure or below, atmospheric pressure being in fact preferred. The preferred space velocity is 0.1 to 1.0 v./v./hr.

The catalyst may be used in the form of a fixed bed, a moving bed or a fluidised bed. Since it is readily regenerated by burning oif carbonaceous deposits in a stream of oxygen-containing gas it is particularly suitable for fluidised or moving bed processes.

The feedstock used should boil within the gasoline or naphtha range (i.e. up to 200 C.) and may be pure hydrocarbons, for example straight chain paratfins or cycloparafi'ins, or mixtures of hydrocarbons. Preferably a major proportion of the feedstock boils below 100 C.

Thus according to one embodiment of the invention, the feedstock may be a straight-run gasoline fraction. By treatment according to the present invention gasolines or gasoline blending components having a research octane number (clear) of at least 90 may be obtained from such fractions. With feedstocks at the lower boiling end of the gasoline range the products will also have a high volatility and may be for example at least 50% volume evaporated at 100 C. A particularly preferred feedstock is a light gasoline having an end boiling point of about 80 to 120 C.

Patented Dec. 17, 1963 According to a further embodiment, the feedstock may be the product of a previous catalytic reforming process so that the present invention includes a two-stage reforming process designed to produce aromatics and high octane gasoline fractions with preferably a research octane number (clear) of the order of 100. Any convenient reforming process may be used as the first stage, but those employing a catalyst of platinum on a support containing aluminium oxide with or Without halogen are preferred, such processes being hereinafter referred to as platinum reforming processes and the products as platinum reformates.

With a two-stage process, the whole of the reformate from the first stage may be reformed in the second stage. Alternatively the reformate may be fractionated and a portion only subjected to the further treatment. The portion may be a lower boiling relatively aromatic free fraction, preferably one with an end boiling point below C. or a higher boiling fraction still containing some non-aromatic hydrocarbons. Alternatively the reformate may be solvent extracted and the raflinate or a fraction thereof subjected to the further treatment. If desired, the product may be recombined with the untreated fraction or the solvent extract as the case may be, but it may also be combined with other high octane components, for example heavy cat. cracked gasoline or alkylate.

The catalyst may be prepared by any convenient method.

Examples of suitable methods are:

(1) impregnation of the alumina base with a solution containing the constituents, preferably in the form of salts. The base may be impregnated with all the constituents together, or two or more solutions containing different constituents may be used in succession. The impregnated base is dried and calcined.

(2) The alumina base may be co-precipitated from a solution, containing aluminium and either chromium or beryllium or both, with alkali, and the precipitate Washed, dired, and calcined. The alkali metal may be subsequently added by impregnation, together with any constituent not co-precipitated. The catalyst is then again dried and calcined.

(3) An insoluble chromium or beryllium compound or both may be milled into the alumina base, further constituents added by impregnation and the catalyst dried and calcined.

(4) As for method 3 above except that the insoluble compound or compounds is suspended in a solution of an aluminium compound from which the alumina is precipitated.

The present invention includes a catalyst comprising chromium oxide on a support, preferably alumina, the catalyst containing also a minor proportion (with respect to the chromium oxide) of beryllium and a minor proportion (with respect to the chromium oxide) of an alkali metal, preferably potassium. The beryllium and .the alkali metal are preferably present in the form of oxides. The catalyst may contain minor amounts of one or more other promoters as detailed above and the preferred proportions of catalyst components are also as set out above.

The invention is illustrated by the following examples:

EXAMPLE 1 A solution containing 24 g. Analar chromium trioxide, 4 g. Analar potassium nitrate (KNO 5.5 g. beryllium nitrate [Be(NO .3H O] and 3 g. Analar" nickel nitrate [Ni(NO .6H O] was used to impregnate 160 g. of alumina which had previously been calcined at 550 C. for two hours. The impregnated alumina was then dried for one hour at C. and calcined for two hours at 550 C.

EXAMPLE 2 A solution containing 24 g. Analar chromium trioxide, 4 g. Analar potassium nitrate (KNO 14 g. beryllium nitrate [Be(NO .3H O], 3.5 g. Analar cobalt nitrate [Co(NO .6H O] and 3.5 g. Analar nickel nitrate [Ni(NO .6H O] was used to impregnate 160 g. of alumina which had previously been calcined at 550 C. for two hours. The impregnated alumina was then dried for one hour at 130 C. and calcined for two hours 10 at 550 C.

Table 1 Reaction temperature 475 0. 530 C.

Debutanised Exit gas Debutanised Exit gas product product Chromia/ Feed alumina catalyst Octane Yield, Hzcon- Octane Yield H2 coupromoters number percent Make, tent,pernumber percent Make, tent,perresearch, wt. s.e.f./b. cent vol. research, wt. s.c.f./b. cent vol.

clear clear Light 80.8 96.9 517 86.8 100.0 82.5 1,345 83.3 platinum 98. 8 88. 5 1, 100 89.0 103. 8 69. 5 1, 889 79. reiormate. 96. 3 87. 5 104. 8 68.0 84.5 81.8 1,379 89.0 06.7 60.1 2,305 0 EXAMPLE 3 EXAMPLE 5 A lower boiling fraction of a reformate obtained by hydroforming a naphtha fraction over a catalyst of platinum, alumina and combined halogen had an ASTM boiling range of 44 C.110 C. and an octane number (research) clear of 80.0. This lower boiling fraction was Example 4 was repeated using a catalyst with the following composition:

Percent wt. Chromium oxide (expressed as Cr O l0 Beryllium oxide (expressed as BeO) 1.0 Potassium oxide (expressed as K 0) 1.0 Nickel oxide (expressed as NiO) 0.5 Cobalt oxide (expressed as C00) 0.5 Alumina Balance In addition comparative runs were carried out using a catalyst identical with the above except that it contained no beryllium.

The results are set out in Table 2 below.

Table 2 Reaction temperature 475 0. 530 C.

Debutanised Exit gas Debutanised Exit gas product product Chromia/ Feed alumina catalyst Octane Yield, Hz con- Octane Yield Hzconpromoters number percent Make, tent,pernumber percent Make, tent,perresearch, wt. s.c.f./lo. cent vol. research, Wt. s.c.f./b. cent vol.

clear clear gg CO-Nl-BO-K 96.9 83.7 984 89.0 103.7 70.8 196.0 32.0 rel-mate. Co-Nr-K 07. 3 83. 6 968 81. 5 103. 6 66. l 180. 2 80. 0

treated under the following process conditions:

Pressure Atmospheric. Space velocity 0.2 v./v./hr. Recycle gas None.

Runs were carried out at two temperatures475 C. and 530 C. Four catalysts were used as follows:

The results show the improvement in yield obtained at the higher temperature by the addition of beryllium to the catalyst.

EXAMPLE 6 A light gasoline having an ASTM boiling range of 41.5 C.-103 C. and an octane number (research) clear of 58.7' was treated under the following process conditions:

Pressure Atmospheric. Space velocity 0.2 v./v./hr. Recycle gas None. Process period 5 hours.

Runs were carried out at two temperatures-475 C. and 530 C.

Three catalysts were used as follows: (i) A catalyst prepared as described in Exampie l and having the composition:

Percent wt. Chromium oxide (expressed as Cr O r Beryllium oxide (expressed as BeO) 0.4 o Nickel oxide (expressed as NiO) 0.4 iotassium oxide (expressed as K 0) 1.0 Alumina Balance 6 all percentages being by weight of total catalyst material stable at 550 C., at a temperature of 450 to 580 C., at a pressure not in excess of about 50 psi. ga., at a space velocity of 0.1 to 1.0 v./v./hr., and in the absence or" added hydrogen to the reaction Zone, and recovering a product having an increased aromatic content.

2. A process for the treatment of a petroleum feedstock consisting essentially of non-aromatic hydrocarbons boiling within the range encompassed by the gasoline and naphtha range to produce a product having an increased aromatic content, comprising contacting the feedstock in a reaction zone with a catalyst consisting essentially of 5 to of chromium oxide, expressed as Cr O 0.1 to 5% of beryllium, expressed as BeO; 0.11 to 5% of an alkali metal, expressed as alkali metal oxide, about 0.1 to 5% of nickel, expressed as NiO; about 0.1 to 5% of cobalt, expressed as C00, and balance alumina, all percentages being by weight of total catalyst material stable at 550 C., at a temperature of 450 to 580 C., at a pressure not in excess of about p.s.i. ga., at a space velocity of 0.1 to 1.0 v./v./hr., and in the absence of Table 3 Reaction temperature 475 0. 530 C.

Debutanised Exit gas Dcbutanised Exit gas product product Chrornia/ Feed alumina catalyst Octane Yield, Hz con- Octane Yield, Hz con promoters number percent Make, tent,pernumber percent Make, tent,perresearch, wt. s.c.i./b. cent vol. research, wt. s.c.f./b. cent v01 clear clear Light 84. 5 81. 1379 89. 0 96. 7 60. 1 2305 78. 0 gasoline. 82.1 86.3 1300 83.0 99. 7 G3. 5 2461 79. 5 82. 5 83.0 95. 0 60. 0

We claim: added hydrogen to the reaction zone, and recovering a i. A process for the treatment of a petroleum feedstock consisting essentially of non-aromatic hydrocarbons boiling within the range encompassed by the gasoline and naphtha range to produce a product having an increased aromatic content, comprising contacting the feedstock in a reaction zone with a catalyst consisting essentially of 5 to 25% of chromium oxide, expressed as Cr O 0.1 to 5% of beryllium, expressed as BeO; 0.1 to 5% of an 0 alkali metal, expressed as alkali metal oxide, about 0.1 to 5% of nickel, expressed as NiO, and balance alumina,

product having an increased aromatic content.

References Cited in the file of this patent UNITED STATES PATENTS 2,441,297 Stirton May 11, :1948 2,705,733 Nonnenmacher et al Apr. 5, 1955 2,754,345 Kirshenbaum July 10, 1956 2,787,583 McGrath et a1 Apr. 2, 1957 2,897,135 Doumani July 28, 1959 2,898,290 Swabb Aug. 4, 1959 

1. A PROCESS FOR THE TREATMENT OF A PETROLEUM FEEDSTOCK CONSISTING ESSENTIALLY OF NON-AROMATIC HYDROCARBONS BOILING WITHIN THE RANGE ENCOMPASSED BY THE GASOLINE AND NAPHTHA RANGE TO PRODUCE A PRODUCT HAVING AN INCREASED AROMATIC CONTENT, COMPRISING CONTACTING THE FEEDSTOCK IN A REACTION ZONE WITH A CATALYST CONSISTING ESSENTIALLY OF 5 TO 25% OF CHROMIUM OXIDE, EXPRESSED AS CR2O3; O.1 TO 5% OF BERYLLIUM, EXPRESSED AS BEO; 0.1 TO 5% OF AN ALKALI METAL, EXPRESSED AS ALKALI METAL OXIDE, ABOUT 0.1 TO 5% OF NICKEL, EXPRESSED AS NIO, AND BALANCE ALUMINA, ALL PERCENTAGES BEING BY WEIGHT OF TOTAL CATALYST MATERIAL STABLE AT 550*C., AT A TEMPERATURE OF 450 TO 580*C., AT A PRESSURE NOT IN EXCESS OF ABOUT 50 P.S.I. GA., AT A SPACE VELOCITY OF 0.1 TO 1.0 V./V./HR., AND IN THE ABSENCE OF ADDED HYDROGEN TO THE REACTION ZONE, AND RECOVERING A PRODUCT HAVING AN INCREASED AROMATIC CONTENT. 